This invention relates to monitoring the internal condition of a running turbine to discover mechanical defects and undesirable changes in the fluid flow paths.
Turbine blades are subject to erosion after a period of usage and develop pit marks and craters. The stationary parts of the turbine, such as the stationary blade system or internal surfaces of the shell, are susceptible to build up of deposited material. If these internal conditions and others such as blade rubbing and blade failure are monitored and detected early enough, scheduled maintenance may be planned ahead and forced outages reduced. Since erosion and deposit buildup will reduce turbine efficiency, the monitoring technique may also serve indirectly as a turbine efficiency monitor. The foregoing remarks are especially true of a large steam turbine-generator combination.
The present state of the art consists of monitoring temperature and static pressures to determine internal changes. An object of this invention is to provide a greater sensitivity in detection than is presently available. Due to the increased sensitivity, incipient failures may be detected earlier so that proper measures can be taken to alleviate the problem. A more efficient maintenance schedule can be devised.